Dynamic approach to the reliability analysis for the Service Water System of a Candu 6 nuclear power plant

A research activity based on the application of dynamical methodologies for Probability Safety Assessment is currently in progress at ACTA Srl, spinoff of the University of Pisa, and at the Department of Mechanical, Nuclear and Production Engineering (DIMNP) of the same University. The present research activity has been performed in collaboration also with Ansaldo Nucleare SpA and regards the Service Water System of a CANDU 6 nuclear power plant. Improvements of its reliability enhance safety of the whole plant. The use of a dynamic methodology permits to consider temporal features in the reliability study of the system. Consistently with the operative experience, the analysis shows that the most critical components are the active ones (i.e. pumps), followed by the passive components (i.e. tubes). On the basis of the obtained results, design and management variations could improve the plant reliability: they allow an unreliability reduction respectively of 70% and 30%.